// electric.c -- calculates electric bill
#include <stdio.h>
#define RATE1 0.13230 // rate for first 360 kwh
#define RATE2 0.15040 // rate for next 108 kwh
#define RATE3 0.30025 // rate for next 252 kwh
#define RATE4 0.34025 // rate for over 720 kwh
#define BREAK1 360.0 // first breakpoint for rates
#define BREAK2 468.0 // second breakpoint for rates
#define BREAK3 720.0 // third breakpoint for rates
#define BASE1 (RATE1 * BREAK1)
// cost for 360 kwh
#define BASE2 (BASE1 + (RATE2 * (BREAK2 - BREAK1)))
// cost for 468 kwh
#define BASE3 (BASE1 + BASE2 + (RATE3 *(BREAK3 - BREAK2)))
//cost for 720 kwh
int main(void) {
  double kwh; // kilowatt-hours used
  double bill; // charges
  printf("Please enter the kwh used.\n");
  scanf("%lf", &kwh);  // %lf for type double
  if (kwh <= BREAK1)
    bill = RATE1 * kwh;
  else if (kwh <= BREAK2) // kwh between 360 and 468
    bill = BASE1 + (RATE2 * (kwh - BREAK1));
  else if (kwh <= BREAK3) // kwh betweent 468 and 720
    bill = BASE2 + (RATE3 * (kwh - BREAK2));
  else                    // kwh above 680
    bill = BASE3 + (RATE4 * (kwh - BREAK3));
  printf("The charge for %.1f kwh is $%1.2f.\n", kwh, bill);

  return 0;
}
